Automated E-tran application

ABSTRACT

Techniques for text entry using gestures are disclosed. As disclosed, a camera may capture a frame and the face of the user can be detected therein. Landmarks can be aligned to the face in the captured frame. A left eye image and a right eye image may be extracted from the captured frame. The left eye image and the right image each may be resized and compared to a calibration template. A direction of eye gaze may be determined based upon the comparison. A character or word may be predicted based upon the determination of the direction of eye gaze and a known configuration of an eye gaze board (e.g., an E-tran board). The predicted character or word can be included as a part of a text-based message.

FIELD OF THE DISCLOSURE

The present disclosure relates generally to techniques for low-cost,portable, and robust eye gesture communication system and moreparticularly, to an eye gaze board application.

BACKGROUND

Eye gaze boards (also known as eye transfer boards or E-tran boards) oreye gaze keyboards (e.g., a digital keyboard) are a common communicationsolution for people with Amyotrophic Lateral Sclerosis (ALS), or whootherwise have very limited movement but have volitional eye movements.ALS is a neurodegenerative disease that causes atrophy of motor neuronsleading to the loss of muscle movement. The muscles that control eyemovement are usually spared until the final stages of the disease. Thus,eye gaze boards enable communication for individuals with ALS or thelike until the late stages of the disease.

High technology gaze recognition systems can also be dwell-based systems(i.e., the user dwells their gaze on a key for a period, typicallyseveral hundred milliseconds, in order to select the key). Specializedhardware set-ups can be used in eye gaze tracking systems such ashead-mounted eye trackers that keep the eyes and the camera close andrelatively static during head movement. Still other high-tech systemscan mount a camera on a computer monitor and find pupil locations basedon reflections. Unfortunately, these and other high-tech eye gazekeyboards have several problems: (1) the hardware for commercialgaze-operated keyboards is relatively expensive ($500˜$3,000 U.S.dollars); (2) the eye tracker requires calibration before each use; (3)the eye tracker does not work in certain conditions that interfere withinfrared light, such as outdoors; and (4) the system requires a stand tokeep it relatively static with respect to the patient, which makes itdifficult to use in certain situations such as in a car or in bed.Notably, there are no eye trackers for a mobile device, and no eyetrackers that are integrated into a mobile device.

Eye-gaze transfer (“E-tran”) boards are an alternative, low-techsolution to the commercial gaze-operated keyboards. An E-tran boardtypically is printed on a transparent plastic board. A typicalconfiguration for an E-tran board has, for example, 8 quadrants spacedaround a hole in the center of the board. Each quadrant has, forexample, six letters in it. A communication partner holds up the boardto face the patient (e.g., a person with ALS) while the communicationpartner observes the patient through the hole in the center of theboard. A person with ALS can communicate using an E-tran board byfocusing gaze on selected characters on a translucent board, and acommunication partner (e.g., a caregiver or an interpreter) interpretsthe gaze. Selection of a letter, for example, is performed by two gazes.The first gaze indicates the quadrant, and the second gaze indicates theposition of the letter within the indicated quadrant. The communicationpartner interprets each eye-gaze and can confirm the patient's selectionfor each eye-gaze (e.g., by having the patient blink or stare at thecenter of the board). Other low-tech systems rely upon the user (e.g.,individual with ALS) having the ability to move a mouse, for example, orlack calibration to a particular device, user, and/or lightingcondition.

E-tran boards have several drawbacks: (1) their cost is relatively lowcompared to gaze-tracking systems, but is not negligible (˜100 U.S.dollars); (2) the large plastic board (e.g., ˜35 cm by ˜45 cm) is noteasily portable; (3) patients need to perform two eye gazes to enter onecharacter, which can require more than 8 seconds including additionaltime to correct any mistakes; and (4) are challenging to master.Communication partners find gaze interpretation has a high learningcurve, as they have to decode and remember entered characters andpredict words. Furthermore, they provide relatively slow communicationrates.

Thus, current eye-tracking input systems for people with ALS or othermotor impairments are expensive, not robust under various lightconditions (e.g., in sunlight or low light), and require frequentre-calibration and substantial, relatively immobile setups.

SUMMARY

According to an embodiment, a system for entering text using an E-tranboard is disclosed that includes a camera, a database, and a processor.The camera may capture one or more frames that include a face of a user.The database may be configured to store the one or more frames from thecamera. The processor may be communicatively coupled to the camera andthe database. The processor configured to detect a face in the capturedone or more frames and align landmarks to the face in the captured oneor more frames. The processor may be configured to extract a left eyeimage and a right eye image of the face from the captured one or moreframes. The extraction may be based upon the landmarks aligned to theone or more frames. The left eye image may be resized to a size matchingone of a calibrated set of left eye images and the right eye image maybe resized to a size matching one of a calibrated set of right eyeimages. The resized images and/or a given calibrated may be at least 30pixels by at least 15 pixels in size. The processor may be configured tocompare the resized left eye image to a calibrated set of left eyeimages for the user. Each image in the calibrated set of left eye imagesmay correspond to a known eye gaze direction for a left eye of the user.The processor may be configured to compare the resized right eye imageto a calibrated set of right eye images for the user. Each image in thecalibrated set of right eye images may correspond to a known eye gazedirection for a right eye of the user. In some configurations, theprocessor may convert the left eye image to hue, saturation, and value(HSV) color space and retain only the value portion. Similarly, it mayconvert the right eye image to HSV color space and retain only the valueportion.

The processor may determine a direction of eye gaze based upon thecomparison of the resized left eye image to the calibrated set of imagesfor the left eye and the comparison of the resized right eye image tothe calibrated set of images for the right eye. A character may bepredicted based upon the determination of the direction of eye gaze anda known configuration of an eye gaze board (e.g., an E-tran board orkeyboard). The predicted character may be included as a part of atext-based message. The processor may be configured to receive one ormore eye gazes from the user to form a sequence of eye gazes. Each eyegaze may correspond to a quadrant of an E-tran board containing a groupof characters. The processor may be configured to predict a word basedupon the sequence of eye gazes.

In some instances, the processor may determine at least one wordassociated with the predicted character based upon the predictedcharacter. The processor may receive a selection of at least one wordassociated with the predicted character. The processor may be configuredto cause an audible or visible indication of the predicted characterand/or word. In some instances the processor may be configured toreceive a gesture from the user and perform an action based upon thegesture. In some configurations, the action may be to delete thepredicted character from the text-based message.

In some configurations, the processor may be configured to generate thecalibration template that includes the calibrated set of left eye imagesand the calibrated set of right eye images. The processor may receive anindication of eye gaze of the user in a direction. It may receive asecond at least one frame of the user from the camera. The processor maybe configured to detect the face of the user in the second at least oneframe. Landmarks may be aligned to the face in the captured second atleast one frame. The processor may extract a calibrated left eye imageand a calibrated right eye image of the face from the second at leastone frame. In some configurations, landmarks may be aligned to the faceto improve the accuracy of the system. In some configurations, thecalibrated left eye image may be resized to a standard size such as 80pixels by 40 pixels) and be at least 30 pixels by at least 15 pixels.Similar parameters may be applied to the calibrated right eye image(e.g., it may be resized to at least 30 pixels by at least 15 pixels).The calibrated left eye image and the calibrated right eye image may bestored to the database as part of the calibration template for thedirection of eye gaze.

In some configurations the processor may determine the lightingcondition the user is in based upon the amount of light detected by thecamera. The lighting condition may be associated with the calibrationtemplate.

According to an embodiment, a computer-implemented method is disclosed.A camera may capture at least one frame that includes a user's face. Theface of the user can be detected in the captured at least one frame.Landmarks can be aligned to the face in the captured at least one frameby the processor. A left eye image and a right eye image of the face maybe extracted from the at least one frame. The extraction may utilize thealigned landmarks to extract the left eye image and/or the right imageto improve the accuracy of eye detection. The left eye image and theright image may each be resized to a size matching one of a set ofcalibrated left eye and/or right eye images. The set of calibrated lefteye and/or set of calibrated right eye images may have a standard sizesuch as 80 pixels by 40 pixels. The size of the calibrated image is notlimiting so long as it is at least 30 pixels by at least 15 pixels. Theresized left eye image can be compared to a calibrated set of left eyeimages for the user. Each image in the calibrated set of left eye imagesmay correspond to a known eye gaze direction for a left eye of the user.The resized right eye image may be compared to a calibrated set of righteye images for the user. Each image in the calibrated set of right eyeimages may correspond to a known eye gaze direction for a right eye ofthe user. In some configurations, the left eye image may be converted tohue, saturation, and value (HSV) color space and retain only the valueportion. Similarly, the right eye image may be converted to HSV colorspace and retain only the value portion.

A direction of eye gaze may be determined based upon the comparison ofthe resized left eye image to the calibrated set of images for the lefteye and the comparison of the resized right eye image to the calibratedset of images for the right eye. A character may be predicted based uponthe determination of the direction of eye gaze and a known configurationof an eye gaze board (e.g., an E-tran board). The predicted charactercan be included as a part of a text-based message. One or more eye gazesmay be received from the user to form a sequence of eye gazes. Each eyegaze may correspond to a quadrant of an E-tran board containing a groupof characters. A word may be predicted based upon the sequence of eyegazes.

In some instances, at least one word associated with the predictedcharacter may be determined based upon the predicted character and/orany preceding predicted characters. A selection of at least one wordassociated with the predicted character may be received. An audible orvisible indication of the predicted character and/or word may beprovided. In some instances, a gesture from the user may be received andan action may be performed based upon the gesture. In someconfigurations, the action may be to delete the predicted character fromthe text-based message.

In an implementation, a calibration template may be generated. Thecalibration template may include a calibrated set of left eye images andright eye images. An indication of eye gaze of the user in a directionmay be received. A second at least one frame of the user may becaptured. The face of the user in the second at least one frame may bedetected. Landmarks may be aligned to the captured second at least oneframe. A calibrated left eye image and a calibrated right eye image ofthe face may be extracted from the second at least one frame. In someconfigurations, the extraction may be based upon the landmarks alignedto the detected face. The calibrated left eye image may be resized to atleast 30 pixels by at least 15 pixels (including a size such as 80pixels by 40 pixels) and the calibrated right eye image may be resizedto at least 30 pixels by at least 15 pixels (including a size such as 80pixels by 40 pixels). The calibrated left eye image and the calibrationright eye image may be stored as part of the calibration template forthe direction of eye gaze.

In some configurations the lighting condition the user is in may bedetermined based upon the amount of light detected by the camera. Thelighting condition may be associated with the calibration template.

According to an embodiment, a non-transitory computer readable mediumhaving stored thereon computer readable instructions that are executableto cause one or more processors to perform operations is provided. Acamera may capture at least one frame that includes a user's face. Theface of the user can be detected in the captured at least one frame.Landmarks can be aligned to the face in the captured at least one frameby the processor. A left eye image and a right eye image of the face maybe extracted from the at least one frame. In some configurations, theextraction may be based upon the landmarks aligned to the face. The lefteye image and the right image may each be resized to a size matching acalibrated image size (i.e., at least 30 pixels by at least 15 pixels,including a standard size of 80 pixels by 40 pixels). The resized lefteye image can be compared to a calibrated set of left eye images for theuser. Each image in the calibrated set of left eye images may correspondto a known eye gaze direction for a left eye of the user. The resizedright eye image may be compared to a calibrated set of right eye imagesfor the user. Each image in the calibrated set of right eye images maycorrespond to a known eye gaze direction for a right eye of the user.

Based upon the executable instructions, a direction of eye gaze may bedetermined based upon the comparison of the resized left eye image tothe calibrated set of images for the left eye and the comparison of theresized right eye image to the calibrated set of images for the righteye. A character may be predicted based upon the determination of thedirection of eye gaze and a known configuration of an eye gaze board(e.g., an E-tran board). The predicted character can be included as apart of a text-based message.

Additional features, advantages, and embodiments of the disclosedsubject matter may be set forth or apparent from consideration of thefollowing detailed description, drawings, and claims. Moreover, it is tobe understood that both the foregoing summary and the following detaileddescription are exemplary and are intended to provide furtherexplanation without limiting the scope of the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the disclosed subject matter, are incorporated in andconstitute a part of this specification. The drawings also illustrateembodiments of the disclosed subject matter and together with thedetailed description serve to explain the principles of embodiments ofthe disclosed subject matter. No attempt is made to show structuraldetails in more detail than may be necessary for a fundamentalunderstanding of the disclosed subject matter and various ways in whichit may be practiced.

FIG. 1A is an example of an eye gaze board according to a disclosedimplementation.

FIG. 1B is an example of an eye gaze board according to a disclosedimplementation that has a different configuration than the eye gazeboard illustrated in FIG. 1A.

FIG. 2 is an example overview of the three features of the disclosedimplementations herein including: eye gaze recognition, text prediction,and a text entry interface.

FIG. 3A is an example of the calibration process according to animplementation disclosed herein.

FIG. 3B is an example of the user interface associated with thecalibration process and examples of the calibration templates forspecific eye gestures according to an implementation disclosed herein.

FIG. 4 is an example of the eye gaze detection as applied to a useraccording to a disclosed implementation.

FIG. 5 is an example of the process for entering a character in atext-based message based upon a direction of a user's eye gaze relativeto an E-tran board according to an implementation disclosed herein.

FIG. 6A is an example of text entry via a user interface according to animplementation.

FIG. 6B illustrates another example of the user interface according toan implementation disclosed herein.

FIG. 7 is an example configuration of a system according to animplementation disclosed herein that includes a camera, a database, anda processor.

FIG. 8 is an example computer (e.g., electronic device such as asmartphone, tablet, laptop, personal computer, etc.) suitable forimplementing embodiments of the presently disclosed subject matter.

FIG. 9 shows an example network arrangement according to an embodimentof the disclosed subject matter.

DETAILED DESCRIPTION

Disclosed is a low-cost, portable, and robust eye gesture or eyegaze-based communication system for individuals with ALS that isrelatively easy for users (e.g., patients) and communication partners touse. As an example, the disclosed implementations can be performed on amobile device to capture eye gaze gestures and interpret them ascharacters using computer vision techniques. The system is as portableas a mobile phone, or other electronic device such as a tablet orlaptop. Furthermore, users can perform a single eye gesture to enter acharacter instead of the two gestures required of conventional E-tranboards. An eye gesture may refer to an eye gaze in a particulardirection, closed eye(s), an eye wink, The system can record the enteredcharacter(s) to automatically predict a word. Compared to commercial eyegaze trackers, the disclosed system (1) has no additional cost otherthan a device such as a smartphone, which most people already own; (2)it only needs a one-time calibration; and (3) it does not require abulky stand, as a communication partner can hold the phone. In addition,the system has the ability to account for different lighting conditionsfor which conventional eye tracking systems are unaffordable orimpractical. Thus, the disclosed system is relatively low-cost,portable, easy-to-learn, and robust, and it has a relatively highercommunication throughput as compared to a conventional plastic E-tranboard.

An example of an eye gaze board 100 is illustrated in FIG. 1A. Theexample eye gaze board 100 contains four quadrants 102, 104, 106, 108,each of which contains a grouping of letters. The implementations of thepresent application are not limited to the configuration of the eye gazeboard 100 shown in FIG. 1A. The number of quadrants may be varied toinclude more or less quadrants than four, and the content of eachquadrant can be altered to suit a particular user or to includeadditional/different content. For example, a quadrant may include “Yes”while another quadrant may include “No.” As another example, a quadrantmay include a series of numbers. In still another example, the displayedeye gaze board 100 may include a blank space or a hole in the center andhave other quadrants distributed around the center space. FIG. 1B is anexample of an electronically-represented eye gaze board 110 according toa disclosed implementation that has a different configuration than theeye gaze board illustrated in FIG. 1A 100. The eye gaze board of FIG. 1B110 has four quadrants with letters 112, 114, 116, 118, as well as ablank space in the middle 120. As previously stated, the number ofquadrants and content thereof can be varied to suit a particular user'spreferences or situation.

The eye gaze board 100 can be printed out and taped to the back of asmartphone (or other electronic device), for example. As anotherexample, it can be displayed electronically to the user on theelectronic device or through the use of a second device that includes ascreen (e.g., a monitor, a second smartphone, a tablet, a laptop, etc.).Because the configuration of the eye gaze board 100 can be customized,the system may have a default configuration such as the example providedin FIG. 1A, or it may request a user or communication partner toindicate the number of quadrants and the content of each respectivequadrant. The configuration can be stored to the device, and loaded uponrequest such that the system utilizes the loaded eye gaze boardconfiguration and performs analysis of eye gestures based upon theE-tran board configuration. Thus, the system may receive an indicationof the configuration of the E-tran board 100 so that it can predict acharacter and/or word based upon the E-tran board 100 configuration.

FIG. 2 is an example overview 200 of the three features of the presentsystem, including: eye gesture or eye gaze recognition 210, textprediction 220, and a text entry interface 230, that provides feedbackto the user (e.g., a person with ALS) and/or the communication partner.The system can include an algorithm to robustly recognize eye gesturesof a user in real time on a hand-held smartphone or other electronicdevice, and decode these gestures into predicted utterances. The systemcan include a user interface to facilitate the user's and communicationpartner's roles.

Beginning with eye gaze recognition at block 210 in FIG. 2, the systemcan robustly recognize eye gestures for both eyes. For example, thesystem can recognize: look up, look down, look left, look right, lookcenter, and close eyes. Additional gestures can be included as needed,such as where the E-tran board includes more than four quadrants. Forexample, the system can detect directions that are diagonal to up andright, up and left, down and right, and down and left. If the user canwink (e.g., closing only one eye at a time), the system can alsoassociate winking the left eye or the right eye with a particularfunction. Thus, the system can receive a gesture and, based on thegesture, perform an action. The action may include, deleting a characteror word, confirming a character or word, indicating the end of asentence, and/or manipulating other elements of the user interface. Forexample, the gesture recognition may allow a user to control variouselements of the operating system or user interface (e.g., close window,go back on a web browser, open a new document, launch an application,close an application, etc.).

Before the system can be used for eye gaze detection 210 as describedabove with respect to FIG. 2, the system can be calibrated to aparticular user. Each user likely has unique facial features and/orcapabilities; thus, the calibration process can allow the system todetect the eye gestures for a particular user. The system can collect aset of eye gestures from the user as calibration templates. As anexample, a communication partner can hold a phone with a rear camerafacing the user and press a “calibrate” button that appears on thescreen of the phone as part of the user interface for the disclosedsystem. The phone (or other device) can emit an audio or visual cue toindicate to the user to prepare for the calibration process. The systemmay then instruct the user to, for example, look up, down, left, right,center, and to close both eyes. As mentioned earlier, the number ofdirections may be customized based upon the number of quadrants and/orgestures desired. If the system utilizes fewer quadrants, then it mayonly instruct the user to look in fewer directions. Similarly, if thesystem utilizes more quadrants, then it may request the user to look inmore directions, such as look up and right, look up and left, look downand left, and look down and right. A “set” of calibrated images mayrefer to the collection of images for each direction that can becollected during the calibration process as disclosed herein. Generally,the template matching will be more accurate the more distinct the eyegazes are from each other.

The calibration sequence can be performed in approximately ten seconds.Calibration is only required the first time the disclosed application isoperated, or if lighting conditions vary drastically. Calibrations takenunder different circumstances can be stored, labeled, and loaded orselected as needed, and even transferred between different devices.

An example of the calibration process 300 is illustrated in FIG. 3A. Toobtain a calibration template for eye gaze recognition, the system maybegin by requesting the user to indicate or specify the configuration ofthe E-tran board that is to be used with the system. Based upon thereceived indication, the system may determine the number of eye gazedirections that are possible. For example, the example E-tran board 100shown in FIG. 1A may specify six possible eye gaze directions. Thesystem, therefore, may have preconfigured E-tran boards from which auser or communication partner may make a selection, as well as providefor customized E-tran boards. For a customized E-tran board, the systemmay request the user to specify one or more of the number of quadrants,capabilities of the user (e.g., can the user perform a wink gesture),and/or the number of directions that the customized E-tran board willemploy. The indication of the E-tran board configuration may be storedin a non-transitory computer readable memory.

The calibration process may be initiated by a communication partnerpressing a button in the user interface (e.g., “calibrate”). Thedisclosed system may face a camera of the electronic device towards theuser and the system may provide a series of audible instructions to theuser. Upon initiating the calibration process, the system may direct theuser to perform a sequence of eye gazes in specific directions (e.g.,left, right, up, down, center, closed) corresponding to the particularE-tran board or number of directions/gestures specified. A threequadrant E-tran board may follow a sequence of up, left, right, center,and closed, while a four quadrant E-tran board left, right, up, down,center, closed. The system can associate a particular eye gaze with aparticular direction or gesture during the process by matching the knownsequence with the captured one or more images following instruction toperform a particular eye gaze or gesture. In general, for the purpose ofcalibration, the robustness of the template matching can be improved bydirecting the user to make eye gestures that exaggerated such that eachdirection of gaze is distinct from each other. At 310, the system mayreceive an indication of an eye gaze direction. For example, the systemmay receive an indication that the first direction to be calibrated isthe “up” direction. The system may audibly indicate to the user to lookup by stating “look up” using a speaker, for example. As anotherexample, the system may visually direct the user to look in a particulardirection such as by displaying on a screen an arrow pointing in the updirection.

At least one frame of the user may be captured at 320. As describedabove a camera that faces the user may capture one or more frames of theuser subsequent to directing the user to look in a specified direction.The frames may be stored to computer readable memory. The speed at whichthe user is instructed to perform the next eye gesture by the system canbe manually controlled by the communication partner (e.g., thecommunication partner can direct the system to proceed to the nextgesture), and/or be varied based upon the physical capabilities of theuser. Next, a face is detected in the frame(s) captured by the camera at330. Face detection algorithms are well known to those of ordinary skillin the art and implementations disclosed herein are not limited to aparticular face detection algorithm. As an example, the face detectionalgorithm may define a rectangle that contains the user's face.

At step 340, a calibrated image may be extracted for each eye of theuser. A left eye and/or right eye image can be extracted from the facedetected in a captured image using, for example, a cascade classifiersuch as a Haar feature-based cascade classifier. Other classifiers oralgorithms may be used to detect an eye. In some configurations,landmarks may be aligned to the detected face in the captured at leastone frame. A landmark, for example, may be a user's nose, mouth, eyes,contour of the face, etc. The alignment, for example, may identify thecontours of the face corresponding to the eye. The system may determinea bounding rectangle of eye landmarks (e.g., as indicated by the facialcontours). For example, a bounding rectangle for each eye may beextracted (e.g., one bounding rectangle per eye). Thus, landmarks do notneed to be aligned to the detected face to extract an eye image.Landmarks can improve the accuracy of the system in recognizing an eyegesture.

In some configurations, the calibrated left eye image and/or calibratedright eye image may be resized to an identical size such as 80 pixels by40 pixels. The disclosed implementations provide accurate eye gesturerecognition with extracted image sizes and/or calibrated image sizes ofat least 30 pixels by 15 pixels (i.e., each extracted eye image orcalibrated image is at least 30 pixels by at least 15 pixels). Imagesizes below this size decrease the accuracy of the system to detect adirection of eye gaze. Similarly, if the image size is too large, it canslow processing of the calibration template or detection of eye gazewhen the system is used to predict a character and/or word for a user.Generally, for most uses, image size greater than 500 pixels by 500pixels does not improve the accuracy of the disclosed system. Inaddition, to improve the accuracy of the eye gaze detection, the imagecan be converted to hue, saturation, and value (“HSV”) color space, andonly the brightness value (i.e., the V channel) can be stored. In someconfigurations, the image can be converted to a gray scale image or asingle channel from an RGB image.

The extracted images may be separately processed for step 350. At step350, the calibrated image for each eye for the eye gaze directionindicated at step 310 can be stored to computer readable memory. Thecalibrated left eye image and calibrated right eye image may be labeledto indicate the eye (i.e., left/right) and/or gesture (i.e., up, down,left, right, center, and closed).

FIG. 3B is an example of the user interface 375 associated with thecalibration process and examples of the calibration templates forspecific eye gestures for the left eye 380 and the right eye 382. Insome instances, when a user looks down, eyelashes may cover the user'seyes. Thus, for the look down gesture, users can be instructed to keepeyes as wide open as possible while looking down. As shown in FIG. 3B,the user interface may show the entire frame within view of the camera384, which in this example primarily contains the face of the user. Inaddition, the user interface may allow a user to store the template 386or remove 388 the template. The template may be associated with aparticular location and setting as well such as “Home” and “no glasses.”

Turning now to the recognition algorithm of the instant application,FIG. 4 is an example of the eye gaze detection as applied to a user 400.Beginning at 410, a user's face is captured by a camera. The camera canbe, for example, the rear camera or front camera of a smartphone ortablet, a peripheral camera, etc. The user may have view of an E-tranboard. The configuration of the E-tran board may be indicated to thesystem. The selected E-tran board may be printed out, or it may bedisplayed on a screen that is in view of the user. A communicationpartner may indicate to the system to prepare to generate a text-basedmessage. The user, at 410 may glance in a particular directionassociated with a character in a quadrant of an E-tran board. The imageat 410 is an example of a frame captured of a user's face. At 420, theuser's face may be detected. In some configurations, landmarks may bealigned to the detected face. The image shown at 430 is an example ofthe user's detected face, with dots 435 indicating the alignment oflandmarks to the user's face (e.g., eyes, nose, chin, and mouth). Thesystem can determine the orientation of the user's face based upon thelandmarks and, therefore, can determine whether an image corresponds tothe left eye or right eye. As stated previously, an eye can be extractedfrom a captured image without aligning landmarks.

An image of each of the user's eyes is extracted at 440 as describedabove. An example of an extracted image for one of the user's eyes isshown in the image at 450. In this example, a rectangle that includesthe six landmarks, as indicated by the dots 435 surrounding one of theuser's eyes, can be extracted. At 460, the extracted image at 450 can benormalized by resizing it to a size of at least 30 pixels by 15 pixels.For example, normalizing the extracted image may refer to resizing theextracted image to a size matching the size of one of the calibrated setof left eye images and/or right eye images. The calibrated images mayeach be the same size. In some instances, the image can be converted toHSV color space as described above to improve the accuracy of thedisclosed embodiments. The image shown at 470 is an example of thenormalized image for one of the user's eyes for the eye gaze at 410. At480, the normalized eye image of 470 can be matched to a set ofcalibrated images for the left or right eye. For example, if the imagesat 450 and 470 correspond to the right eye, the system may compare thenormalized right eye image to the calibration templates for the righteye.

Once there is a new or existing calibration for the user, the user mayperforin eye gestures to communicate while a communication partner, forexample, aims the rear phone camera towards the user. In someconfigurations, the user's face may be displayed on the screen of thephone (which can face the communication partner). For each camera frame,the disclosed system can detect the face, extract an image of each eye,and normalizes the eye image. Then the system can classify eye gesturesby matching the normalized eye images extracted from the current videoframe with the calibration templates.

The images shown at 490 correspond to examples of the calibrationtemplates for one of the user's eyes. In order from top to bottom, thecalibrated set of images at 490 correspond to up, down, left, right,center, and closed in this example for a given eye. The system comparesthe normalized eye image of 470 to each of the calibrated set of imagesat 490 to determine which of the calibration images most closelyresembles the eye gaze direction of the normalized image 470. Many imagecomparison algorithms are known, and the presently disclosedimplementations are not limited to a particular image comparisonalgorithm. Because each calibrated template image is associated with aparticular eye gaze direction (e.g., up, down, left, right, center, andclosed), when a match is determined, the user's direction of eye gazecan be determined. Based on the E-tran board configuration, the systemmay determine that that the user has indicated a particular character ina quadrant of the E-tran board that is in the direction of the eye gaze.

FIG. 5 is an example of the process for entering a character in atext-based message 500 based upon a direction of a user's eye gazerelative to an E-tran board. At 510, at least one frame of a user whocan view an E-tran board is captured. The camera can be positioned suchthat the face of the user is in the frame captured by the camera. Aspreviously described, the configuration of the E-tran board may bepreviously indicated and/or entered by a communication partner. At 520,a face in the captured at least one frame may be detected using a facedetection algorithm as described above. A left eye image can beextracted and a right eye image can be extracted 530. Landmarks can bealigned to the detected face in the captured at least one image in someconfigurations to improve the accuracy of the eye gesture recognition.As described above, the extracted eye images can be resized to a sizematching one of a set of calibrated left eye and/or calibrated right eyeimages. As described above, the minimum size for an extracted imageand/or calibrated image can be at least 30 pixels by at least 15 pixelsat 540. The calibrated images for the left eye and right eye may beidentically sized to, for example, 80 pixels by 40 pixels. Eachextracted image in such a case may also be resized to 80 pixels to 40pixels.

The resized left eye image can be compared to a calibrated set of lefteye images, and similarly, the resized right eye image can be comparedto a calibrated set of right eye images at 550. As an example, meansquared error (“MSE”) can be computed to measure the difference betweentwo images. MSE can be used to determine the closest match for thenormalized eye images from step 540 to the calibration template thatincludes the set of calibrated images for each eye. Other algorithms maybe utilized to perform the image comparison such as structuralsimilarity and/or sum of absolute differences.

At 560, a direction of eye gaze can be determined based upon the set ofcalibration images that match the normalized image obtained at 540.Based upon the direction of eye gaze determined at 560, a character maybe predicted. For example, a user's eye gaze in the right direction maylead to entry of a character select the right-most quadrant 106 of theE-tran board 100 shown in FIG. 1A. The characters in the right mostquadrant may be ranked based upon a likelihood of use. For example, theprobability that a word beginning with an “M” is substantially morelikely than a word beginning with a “Q.” At step 580, the predictedcharacter may be entered as part of a text-based message. Thus, amongthe characters in the indicated quadrant and a ranking, a character maybe temporarily entered into a text field that is displayed on a screenof an electronic device. For each letter that the user seeks to enter,the prediction can update the prediction of characters entered. Becausethe disclosed implementations require only a single eye gaze to indicatea character, a user can perform a sequence of eye gazes to spell aparticular word where each eye gaze is associated with one character.

Returning to FIG. 2, the second feature of the disclosed system is wordprediction 220. To avoid fatigue of making complex eye gestures, improvelearnability, and improve recognition rates, the disclosed system canuse a small number of simple eye gestures (up/down/left/right) to referto all 26 letters in the English alphabet, using only one gesture percharacter entered (to reduce fatigue and increase throughput). Thedisclosed design can provide for an ambiguous keyboard in which theletters of the alphabet are clustered into four groups that can beindicated with the up, down, left, or right gestures as shown in FIGS. 1and 6A at 100, 610. The system may utilize a word prediction algorithmto predict what word the user is attempting to spell. For example, theword prediction algorithm may utilize the most common words in adictionary, or commonly used words. A predicted word can be displayed ona screen that is visible to the communication partner. The wordpredictions can be updated based upon subsequently received information.For example, if the user performs a subsequent eye gaze, if the userindicates that an incorrect character has been entered and gestures thesystem to delete that character (e.g., with an eye wink), or if the userindicates that there are no additional characters to enter (e.g., byclosing eyes).

FIG. 2 indicates that the final stage of the disclosed implementationsis a text entry interface 230. The text entry interface 230 is notlimited to any particular configuration. FIG. 6A is an example of anE-tran board 610 along with an example of the word prediction interfacebased on a sequence of eye gestures 620. The E-tran board has fourquadrants 602, 604, 606, and 608, and each quadrant has a collection ofletters (e.g., characters). A calibration template for the user for thisE-tran board 610 shown in FIG. 6A may be established by performing thecalibration template generation process described above. A communicationpartner may initiate the text entry process by launching an applicationthat directs hardware of an electronic device to perform the processdescribed with respect to FIG. 5. The process in FIG. 5 may be repeateduntil, for example, a word is entered or selected by the communicationpartner or by the user (e.g., via an eye gesture such as a wink orclosed eyes).

A predictive text algorithm can be utilized to determine possible wordsthat could be created with the letters in the quadrants indicated by agesture sequence. As an example, the disclosed system can use a triedata structure to store common words and their frequencies in oralEnglish. The most common 5000 words (frequency min=4875, max=22,038,615,mean=12,125) from this wordlist can be selected. The communicationpartner can extend the trie to add the user's frequently-used words(including words not in the dictionary such as a name). For a series ofeye gestures with length n, the trie structure can rapidly determinematching words and word frequencies in O(n) time. For a series of eyegestures, the disclosed system can also look up high frequency wordswhose initial characters match the gesture sequence thus far. A list oflikely words based on the current gesture sequence can be displayed on ascreen of an electronic device (e.g., a smartphone) for thecommunication partner. The number of words displayed can be varied. Asan example, in FIG. 6A, each line of words predicted in the sequence612, 614, 616, 618 shows the top four words predicted. Additionalpredictions may be viewed by horizontal/vertical scrolling. Theseprediction and auto-complete features can assist the communicationpartner in predicting possible words while the user is still enteringtext. This can improve throughput of the text entry, and ease theinterpretation burden that is present in using a low-tech E-tran boards.

In the example sequence of eye gazes in FIG. 6A, a user may look down622, look up 624, look right 626, and then look left 626. As the userperforms the sequence of four eye gazes shown in FIG. 6A, the system candetermine a character that corresponds to a quadrant in the direction ofthe eye gaze as described above. Thus, each word shown in the line at612 begins with a letter in the “down” quadrant 608. At line 614, theuser has performed two eye gazes in succession. The second eye gaze isassociated with the “up” quadrant 602. The word prediction algorithm candisplay, for example, the most likely words that begin with a letterfrom the first indicated quadrant and have a second letter from thesecond indicated quadrant. The process of entering characters andupdating the list of displayed words can proceed until an indication isreceived that the user has finished entering characters (e.g., spellinga word) or that the correct word has been predicted. A communicationpartner may speed up the selection of words if it becomes clear to thecommunication partner which word the user intends to spell. For example,the user interface may provide a touch interface that allows thecommunication partner to tap one of the words displayed on the screen.The electronic device may speak the selected word. Similarly, in theevent that the system cannot detect a user's eye gaze (e.g., due to lowlight) or incorrectly detects the user's eye gaze, if the communicationpartner observes the user's eye gaze, the communication partner canselect the appropriate character or word.

As illustrated in the example shown in FIG. 6A, in order to enter theword “TASK,” the speaker first looks down for “T,” then looks up for“A,” looks right for “S,” and looks left for “K.” The predictions aftereach eye gesture in this sequence 622, 624, 626, 628 are shown in FIG.6. To make it easier for the speaker to learn the gesture directionassociated with a given letter, the four groups in the example E-tranboard 610 shown in FIG. 6A are in alphabetical order. As stated above,an alternative letter/character grouping may reduce the conflict ratefor word prediction. Similarly, the number of quadrants, and thereforethe number of detectable eye gaze directions, can be varied. An E-tranboard with fewer quadrants may improve learning how to operate thedisclosed system. For example, the word prediction conflict rate isreasonably low for the E-tran board 610 shown in FIG. 6.

The disclosed implementations, using the eye gaze board shown in FIG. 1Aor 6, were tested on twelve participants (five males and seven females,six individuals without glasses (e.g., with normal uncorrected vision),one individual with contact lenses, and five individuals with frameglasses, all individuals were of ages 20 to 44). Participants had variedskin and eye color. During the study, each participant performed each ofan up, down, left, right, close, and center eye gesture 30 times. Aftereach gesture, the participant was instructed to look back to center.Each participant recorded 300 eye gazes for testing plus an additional150 gazes toward the center. The results of the test are summarized inTable I below:

TABLE 1 Recognition rate for each eye gesture Up Down Left Right CloseCenter Mean 88.6% 75.3% 87.8% 86.9% 77.5% 98.6% Stdev 5.2% 17.5% 4.8%7.4% 13.5% 1.8% Stdev = standard deviation.In general, the percentage shown for “Mean” is the disclosedimplementation's recognition rate for each indicated eye gesture.

The overall accuracy of the disclosed system is 86% of all eye gestures(min.=68%, max.=92%, med.=89%, stdev=6.9%). The center gesture wasrecognized with near perfect accuracy, while the other eye gestures hada high level of accuracy. Looking down and eyes closed were the mostdifficult gestures to distinguish, which is expected based on theirsimilar appearance (see, e.g., FIG. 3B). The accuracy of the system wasconsistent irrespective of age, gender, eye color, or skin color. Whilethe use of contact lenses did not appear to have an effect on theaccuracy of recognition (89.7% accuracy for the one participant withcontact lenses), the use of glasses significantly lowered therecognition accuracy to 80.4% (t(9)=2.714, p=0.024). The use of glassesmay interrupt facial landmark alignment, which can cause a mislabelingof the eye area.

In testing with subjects using the disclosed system and the E-tran boardas shown in FIG. 6A, 3248 unique eye gesture sequences matched 5000words in the trie. 83.5% of sequences matched a unique word, 92.6%matched two or fewer words, 97.7% matched four or fewer words, 99.2%matched six or fewer words, and 99.6% matched 8 or fewer words. Thus,the disclosed system achieves high accuracy despite using a single eyegaze per character and relatively common hardware (e.g., a smartphone ortablet).

As described earlier, the disclosed system can successfully operateunder a variety of lighting conditions, including indoors and outdoors.A calibration template can be established for each particular lightingcondition. In addition, in low light conditions, for example, the systemcan activate the electronic device's camera light (e.g., flashlight), ifsuch hardware exists, to make the user's face visible. To avoid flashburn to the user's eyes, a diffuser such as tape can be placed over thelight. A lighting condition can be determined by detecting an amount oflight received by the camera. The system may determine that a low amountof light is present. For example a low lighting condition may correspondto less than 50 lux. Normal lighting may refer to greater than 100 lux.

In an implementation, the disclosed system can adapt to two majortransformations: it can adapt to scale and to translation. Scale canrefer to an instance where the communication partner moves phone closerto the user. Translation can refer to an instance where the head of theuser is moved slightly, or where the communication partner moves theelectronic device (e.g., phone or camera) while holding it. Thedisclosed can also adapt to the combination of scale and translationsuch as when the communication partner sets the electronic device down,and later holds it in a slightly different position.

The last feature shown in FIG. 2 is text entry via a user interface 230.FIGS. 6A and 6B provide examples of an interface from which predictedwords can be selected from a list. The user and communication partnercan use different interfaces. The user, for example, can see the back ofthe electronic device such as a smartphone. Thus, a text entry interfacewithout a screen can include two components: a sticker displaying thefour quadrant-containing E-tran board (or the like), and an audiofeedback. The communication partner, in this example, can see thesmartphone screen, which can display three components: the fourquadrant-containing E-tran board, a word prediction sequence (see, forexample, 620), and the text input box (see, for example, 630).

As the user begins to enter one character, the user can perform eyemovements in the direction associated with a character in a givenquadrant. In an implementation, once the system detects that the eyeshave settled in one direction, it can speak aloud the direction itdetected (e.g., “Up”). The user can then perform an eye movement toenter the next character. When user mistypes or hears feedbackindicating an incorrect gesture recognition, the user can performanother gesture such as a left eye wink, to delete the word. Othergestures may be utilized including closing eyes for a specified periodof time. If the user directs the system to delete the last characterwith a gesture, the system can remove the last character from thecurrent sequence and/or update the predicted words. When the userfinishes a sequence for an entire word, the user can perform anothergesture such as winking a right eye or looking at the center of theboard for a predetermined amount of time (e.g., two seconds), toindicate the end of the word. The system can speak aloud the first wordprediction based on the series of eye gestures. The speaker can confirmthis prediction by performing an eye gesture, such as winking the righteye again, to confirm the prediction. As another example, the user canperform a gesture to hear the next word prediction. After a word hasbeen confirmed, the word can be added to the sentence being constructedin the text input box. After the user confirms the last word of thesentence, the user can perform a gesture to indicate the end of thesentence such as a right eye wink again. In response to the received eyegesture, the system can play aloud the completed sentence.

With information displayed on the screen of an electronic device, thecommunication partner can speed up the communication process. The textinput box can show the most likely word(s) based on the current gesturesequence, and the length of the word can also indicate the number of eyegestures performed in the current sequence. Even before the userfinishes a word, if the communication partner observes a likely wordprediction based on context of the sentence and/or familiarity with theuser, the communication partner can, for example, say the word aloud ortap the prediction box to have the system play the word aloud. The usercan confirm or reject the prediction by performing an eye gesture suchas by winking the right eye to confirm the entry or winking the left eyeto reject the entry. The present disclosure is not limited to the eyegestures specifically mentioned herein. Other motions can beincorporated into the present implementations to account for the varyingrange of mobility of the user. Examples of other motions that can beutilized in lieu of or in addition to eye gestures include headmovements such as a nod, eye brow movement, etc. If the communicationpartner received confirmation from the user, the communication partnercan add the word to the sentence box, for example, by performing along-press (e.g., at least two seconds) of the word. The user canproceed to begin a gesture sequence for the next word in the sentence.If the user rejects the prediction of the communication partner, theuser can continue to make eye gestures to complete the word. Once theuser indicates the end of the sentence, the communication partner canconfirm the sentence with the user by saying the sentence aloud ortouching the text input box which may prompt the system read thesentence aloud.

FIG. 6B illustrates another example of the user interface according toan implementation disclosed herein. In this example, the eye gaze board650 is a four quadrant 652, 654, 656, 658 board with the alphabetdistributed among the four quadrants 652, 654, 656, 658. A face of theuser 660 is shown with a face recognition box. The user interface 650can display the top overall word predicted 670 based on the currentsequence of eye gestures. The top four word predictions 675 are alsodisplayed in a line. The system may visually indicate the current focusby changing the current word a different color. A user may select adifferent predicted word by performing an eye gesture (e.g., look right)and the system may indicate the next word by speaking the word and/orvisually indicating the selection. The number of words shown can bevaried, and each word can be selected to speed up communication. A textinput box 680 can display the prior words in the communication exchange.When the user indicates the end of a word (e.g., by winking), the systemmay “speak” the word. The word can be added to the text input box. Afterthe user confirms the last word of the sentence, the system may playaloud the entire sentence and the user may indicate whether the sentenceis correct or needs to be edited. Finally, the user interface maydisplay the currently selected calibration template 690. A differenttemplate may be chosen if desired, such as by selecting the“configuration” button 695.

A lab-based usability study was conducted to gauge the relativeperformance, usability, and user preference for the disclosedimplementations. The study involved ten pairs of randomly selected,able-bodied individuals who did not have prior E-tran board experience.The average age of participants was 32 (min.=20, max.=52); fourteenparticipants were male and six were female. Each person was randomlyassigned the role of either the user or the communication partner. Amongthose selected to be a user, five had normal (uncorrected) vision, twowore contact lenses, and three wore glasses. For input methods requiringboth participants, the participants sat approximately 0.5 m apart facingeach other in chairs. A Latin Square Design was utilized tocounterbalance the ordering of the three input methods acrossparticipant pairs. The sentences to be entered during testing were arandomly selected set of eighteen five-word-long sentences (29-31characters each) from the Mackenzie and Sourkeroff phrase sets commonlyused for evaluating text entry techniques.

The user preference among three input or communication methods wasexamined. The three input methods were: (1) a conventional E-tran board,(2) an implementation of the disclosed system operating on a smartphonein which the rear camera faced the user, and the front camera/display ofthe device faces the communication partner (e.g., as illustrated in FIG.6A), and (3) an implementation of the disclosed system in which the useroperates the electronic device independent of a communication partner(e.g., as illustrated in FIG. 6B). In the third input method, theelectronic device (a smartphone in this case) is positioned in a standsuch that a camera and the display face the user (e.g., the user seesthe display). The speaker performs eye gestures as described above inthis input method and indicates the end of a word (e.g., by winking). Inaddition to playing the completed word aloud, the system can visuallyindicate the first predicted word (e.g., by changing the color of theword) to indicate the current focus. The user can perform a subsequenteye gesture to hear the next predicted word and the visual focus mayswitch to that prediction.

For each of the three input methods, participants were provided a brieftutorial on how to use the communication method, and the pair wasallowed to practice until they felt comfortable using the method tocommunicate a two-word example utterance (e.g., “hello world”). Asentence from the testing corpus was privately shared with the user, andthe user was instructed to communicate that sentence as quickly andaccurately as possible to the communication partner without speaking andusing only the current input method. The time from when the user wastold to communicate the sentence until the when the communicationpartner correctly decoded the sentence was recorded. This procedurecontinued until either six sentences had been successfully communicatedor ten minutes had elapsed, at which point the session was halted inorder to avoid excessive fatigue. Participants then completed a shortquestionnaire providing feedback about their experience using thecurrent input method, and took a short break if they felt fatigued.After repeating this procedure for all three communication methods,participants completed a final questionnaire ranking their preferencesamong all three methods.

For each 10-minute session using a given communication method, the userwas asked to communicate six sentences individually or to thecommunication partner. Using the disclosed implementations (i.e., inputmethods 2 and 3), all pairs successfully communicated all six phrases.However, using the conventional E-tran method, pairs completed anaverage of 4 phrases. These data are summarized in Table 2 below:

TABLE 2 The time (in seconds) used to complete a sentence for each inputmethod Mean Median Min. Max. Stdev. Input method 1 1434 122.5 72 29857.4 Input method 2 80.9 77.5 51 132 18.8 Input method 3 77.1 76 56 12011.5Participants, on average, used 137.8 seconds to complete a sentenceusing the conventional E-tran board (input method 1), 80.9 seconds usinga first implementation disclosed herein (input method 2), and 77.1seconds using a second implementation disclosed herein (input method 3).A one-way Analysis of Variance (ANOVA) with repeated measures indicatedthat the mean input time differed significantly between input methods(F(1.067, 9.602)=21.032, p=0.002). Pairwise paired-samples t-tests showthat both of the tested implementations delivered a statisticallysignificant reduction in input time as compared to the conventionalE-tran board (Input method 2 vs. Input method 1: t(9)=4.136, p=0.003;Input method 3 vs. Input method 1: t(9)=3.983, p=0.003).

The questionnaires completed after each input method was performed askedparticipants to indicate their level of agreement with severalstatements about that condition's input method on a 5-point Likert scale(Table 3).

TABLE 3 The user's (U) and communication partner's (C) average agreementlevel (1 = strongly disagree, 5 = strongly agree) on each statement.Input Input Input method 1 method 2 method 3 U C U C U C I feel it isunnecessarily complex 2.9 2.4 1.7 1.7 1.6 2.1 I feel confident to use it3.0 3.3 4.3 4.3 4.3 3.8The Friedman test indicates there were statistically significantdifferences in perceived complexity between the tested input methods(χ²=8.5, p=0.014). A Wilcoxon signed-rank test shows that Input method 2has a statistically significant reduction in perceived complexity overInput method 1 (Z=−2.834, p=0.005). There were no significantdifferences between Input methods 2 and 3 (Z=0.612, p=0.541), or betweenInput method 1 and Input method 3 (Z=−1.794, p=0.073). A Friedman testalso indicates there were statistically significant differences inperceived confidence in correctly communicating using each input methods(χ²=7.4, p=0.024). Participants reported feeling more confident usingInput methods 2 and/or 3 as compared to Input method 1 (Input method 2vs. Input method 1: Z=−2.871, p=0.004; and Input method 3 vs. Inputmethod 1: Z=−1.970, p=0.049).

The study questionnaires also included items from the NationalAeronautics and Space Administration Time Load Index (NASA TLX) scale,reported on a 7-point scale (Table 4).

TABLE 4 The user's (U) and communication partner's (C) average ratings(1 = very low, 7 = very high) for NASA TLX items. Input Input Inputmethod 1 method 2 method 3 U C U C U C Mentally Demanding 4.8 4.5 3.32.5 3.4 2.6 Task Difficulty 3.9 3.5 2.4 2.4 3.1 1.9 FeelStressed/Discouraged 3.9 2.2 2.1 1.9 2.4 1.8Participants rated Input method 1 as more mentally demanding than Inputmethods 2 and/or 3 (Friedman test: χ²=13.5, p=0.001, Input method 2 vs.Input method 1: Z=−3.471, p=0.001; and Input method 3 vs. Input method1: Z=−2.774, p=0.006). Compared to Input method 1, Input methods 2 and 3were considered less difficult to use (Friedman test: χ²=7.0, p=0.03,Input method 2 vs. Input method 1: Z=−2.560, p=0.01; and Input method 3vs. Input method 1: Z=−1.930, p=0.05). Participants indicating feelingless stressed or discouraged when using Input method 3 as compared toInput method 1 (Z=−1.951, p=0.05). For users, using Input method 2significantly reduced feelings of stress and discouragement compared tousing Input method 1 (Z=−2.328, p=0.02).

After completing all sessions, participants ranked all three Inputmethods based on their experience (Table 5). Overall, participantspreferred Input methods 2 and 3 over Input method 1. Input method 1 wasnot selected by any participants as their favorite input method. Aone-sample chi-square test showed a significant difference in therankings of preferences for each system, with Input method 1 most likelyto be ranked as the least favorite by all participants, regardless ofrole (χ²(1, N=20)=9.80, p=0.002).

TABLE 5 The user's (U) and communication partner's (C) average rank (1 =best, 3 = worst) Input Input Input method 1 method 2 method 3 U C U C UC Average Rank 2.9 2.8 1.6 2 1.5 1.2

Communication partners favored Input method 3 as the top-rankedinterface (likely because this mode resulted in less activecommunication partner involvement), χ²(1, N=10)=6.40, p=0.01, whereasparticipants in the user role were not significantly more likely to havea clear preference between Input method 2 or 3, χ²(1, N=10)=0.40,p=0.53.

FIG. 7 is an example configuration of a system according to animplementation disclosed herein that includes a camera 710, a database720, and a processor 730. These components can be integrated into asingle device 700, or be in separate devices. For example, the camera710 can be connected to the system as a peripheral device such as theremote camera. Similarly, the database 720 can be a remote database thatstores, for example, the calibration template for the user. The camera710 can be a red, green, blue (“RGB”) camera typically found in mostportable consumer devices (e.g., laptops, tablet, smartphone). The RGBcamera may detect light in the visible light spectrum. The camera 710can be an infrared camera as well be a hybrid RGB/IR camera. The camera710, database 720, and processor 730 can be connected by a system busand/or a network connection. The device can also include a screen 740,however a screen 740 to display information is not necessary. Asdescribed above, the device may utilize a speaker 750 to provide anaudible indication of a character and/or word. Similarly, the device mayemit a sound to provide direction such as during the calibrationtemplate generation to direct the user to look in a particulardirection.

As described above, the camera 710 can capture at least one frame thatincludes a face of a user. As an example the camera may capture framescontinuously. Each frame can be stored temporarily in the database. Thedatabase can refer to a short term memory such as random-access memory(“RAM”) or a storage drive. The processor 730 may be communicativelycoupled to the camera 710 and the database 720. The processor may beconfigured to receive an indication of the E-tran board configuration.For example the communication partner can select from a predeterminedE-tran board configuration such as the example provided in FIG. 6A, or acustomized E-tran board can be selected. Upon selection of the E-tranboard configuration, the processor may begin analyzing the framescaptured by the camera 710 that are stored in the database 720 asdescribed earlier. For example, during text-based message entry, eachframe captured may be analyzed to detect a face using a face detectionalgorithm.

The processor 730 may be configured to align landmarks to the face ineach captured frame. A left eye image and a left eye image may beextracted. In configurations where landmarks are aligned to the detectedface, the left eye image and/or right eye image may be extracted basedupon the aligned landmarks for each frame. Each of the left eye imageand/or the right eye image extracted from a frame can be resized to asize matching one of a set of calibrated left eye images and/or a set ofcalibrated right eye images. The processor can compare the resized lefteye image to the calibrated set of left eye images as described above.Similarly, the processor can compare the resized right eye image to theset of left eye images as described above.

As an example, a given eye gaze gesture may be performed or detectedwithin a ten frames. Ten frames for each eye, therefore, may be capturedand compared to the respective calibrated set of images for a given eye.The comparison of a frame to an image from the calibration template maybe performed by, for example, MSE. Even if the user has not begun togaze in a given direction at the start of capturing images, over thecollected ten frames for each eye in this example, the majority arelikely to be more similar to the eventual eye gaze direction of theuser. The system may include a threshold level value for MSE, abovewhich a match is determined not to exist to the given direction of eyegaze for a calibrated image. Thus, if 12 of the 20 resized imagesindicate a “right” eye gaze, then the direction of eye gaze can bedetermined as “right.”

The processor 730 can predict a character based upon the comparison ofthe resized image to the calibrated set based upon the determineddirection of eye gaze by the user and the known configuration of theE-tran board. In some configurations, the system may emit a soundthrough the speaker 750 to indicate the determined direction of eyegaze, the predicted character, and/or the predicted word. As anotherexample, the screen 740 may provide a visual indication of thedetermined direction of eye gaze (e.g., by highlighting the quadrant ofthe E-tran board such as the one shown in FIG. 6), by displaying thepredicted character, and/or by displaying the predicted word. The systemmay receive confirmation of the predicted character and/or word bydetecting an eye gesture of the user such as a wink, closed eyes, centergaze, head movement, etc. The predicted character may be included aspart of a text based message. As described above, the processor 730 maybe configured to display the word in a text input box on the screen 740.

In some configurations, the system may utilize two devices, such as twosmartphones. In such a configuration, the screen of a first smartphonemay face the communication partner while the screen of the second devicemay face the user. The camera on the second electronic device facing theuser may be utilized to capture frames of the user. The screen of thesecond electronic device may display the E-tran board, as well as otherinformation such as the text input box and/or the character and/or wordpredictions. The screen of the first electronic device may display theE-tran board, the predicted character, and/or word, and/or the textinput box. In some configurations, the communication partner and theuser may be located in separate locations. The user may have anelectronic device that includes at least a camera, processor, database,and speaker. The electronic device may be positioned to capture the faceof the user. The camera images can be stored on the electronic device orto a remote location for analysis. The result of the analysis (e.g.,direction of eye gaze and/or predicted character and/or word) may beprovided to the communication partner's device and/or the user's device.The communication partner can interact with the system as describedabove. Thus, the system does not require the communication partner andthe user to be collocated. As an example, such an implementation canallow remote communication over a video chat application or the like.

Embodiments of the presently disclosed subject matter may be implementedin and used with a variety of component and network architectures. FIG.8 is an example computer 20 (e.g., electronic device such as asmartphone, tablet, laptop, personal computer, etc.) suitable forimplementing embodiments of the presently disclosed subject matter. Thecomputer 20 includes a bus 21 which interconnects major components ofthe computer 20, such as a central processor 24, a memory 27 (typicallyRAM, but which may also include read-only memory (“ROM”), flash RAM, orthe like), an input/output controller 28, a user display 22, such as adisplay screen via a display adapter, a user input interface 26, whichmay include one or more controllers and associated user input devicessuch as a keyboard, mouse, and the like, and may be closely coupled tothe I/O controller 28, fixed storage 23, such as a hard drive, flashstorage, Fibre Channel network, SAN device, SCSI device, and the like,and a removable media component 25 operative to control and receive anoptical disk, flash drive, and the like.

The bus 21 allows data communication between the central processor 24and the memory 27, which may include ROM or flash memory (neithershown), and RAM (not shown), as previously noted. The RAM is generallythe main memory into which the operating system and application programsare loaded. The ROM or flash memory can contain, among other code, theBasic Input-Output system (BIOS) which controls basic hardware operationsuch as the interaction with peripheral components. Applicationsresident with the computer 20 are generally stored on and accessed via acomputer readable medium, such as a hard disk drive (e.g., fixed storage23), an optical drive, floppy disk, or other storage medium 25.

The fixed storage 23 may be integral with the computer 20 or may beseparate and accessed through other interfaces. A network interface 29may provide a direct connection to a remote server via a telephone link,to the Internet via an internet service provider (ISP), or a directconnection to a remote server via a direct network link to the Internetvia a POP (point of presence) or other technique. The network interface29 may provide such connection using wireless techniques, includingdigital cellular telephone connection, Cellular Digital Packet Data(CDPD) connection, digital satellite data connection or the like. Forexample, the network interface 29 may allow the computer to communicatewith other computers via one or more local, wide-area, or othernetworks. Many other devices or components (not shown) may be connectedin a similar manner (e.g., digital cameras or speakers). Conversely, allof the components shown in FIG. 8 need not be present to practice thepresent disclosure. The components can be interconnected in differentways from that shown. The operation of a computer such as that shown inFIG. 8 is readily known in the art and is not discussed in detail inthis application. Code to implement the present disclosure can be storedin computer-readable storage media such as one or more of the memory 27,fixed storage 23, removable media 25, or on a remote storage location.

FIG. 9 shows an example network arrangement according to an embodimentof the disclosed subject matter. One or more clients 10, 11, such aslocal computers, smartphones, tablet computing devices, and the like mayconnect to other devices via one or more networks 7. As describedearlier, the communication partner may operate a client device that isremote from the device operated by the user (e.g., in separatelocations). The network may be a local network, wide-area network, theInternet, or any other suitable communication network or networks, andmay be implemented on any suitable platform including wired and/orwireless networks. The clients may communicate with one or more servers13 and/or databases 15. The devices may be directly accessible by theclients 10, 11, or one or more other devices may provide intermediaryaccess such as where a server 13 provides access to resources stored ina database 15. The clients 10, 11 also may access remote platforms 17 orservices provided by remote platforms 17 such as cloud computingarrangements and services. The remote platform 17 may include one ormore servers 13 and/or databases 15.

More generally, various embodiments of the presently disclosed subjectmatter may include or be embodied in the form of computer-implementedprocesses and apparatuses for practicing those processes. Embodimentsalso may be embodied in the form of a computer program product havingcomputer program code containing instructions embodied in non-transitoryand/or tangible media, such as floppy diskettes, CD-ROMs, hard drives,USB (universal serial bus) drives, or any other machine readable storagemedium, wherein, when the computer program code is loaded into andexecuted by a computer, the computer becomes an apparatus for practicingembodiments of the disclosed subject matter. Embodiments also may beembodied in the form of computer program code, for example, whetherstored in a storage medium, loaded into and/or executed by a computer,or transmitted over some transmission medium, such as over electricalwiring or cabling, through fiber optics, or via electromagneticradiation, wherein when the computer program code is loaded into andexecuted by a computer, the computer becomes an apparatus for practicingembodiments of the disclosed subject matter.

When implemented on a general-purpose microprocessor, the computerprogram code segments configure the microprocessor to create specificlogic circuits. In some configurations, a set of computer-readableinstructions stored on a computer-readable storage medium may beimplemented by a general-purpose processor, which may transform thegeneral-purpose processor or a device containing the general-purposeprocessor into a special-purpose device configured to implement or carryout the instructions. Embodiments may be implemented using hardware thatmay include a processor, such as a general purpose microprocessor and/oran Application Specific Integrated Circuit (ASIC) that embodies all orpart of the techniques according to embodiments of the disclosed subjectmatter in hardware and/or firmware. The processor may be coupled tomemory, such as RAM, ROM, flash memory, a hard disk or any other devicecapable of storing electronic information. The memory may storeinstructions adapted to be executed by the processor to perform thetechniques according to embodiments of the disclosed subject matter.

The foregoing description, for purpose of explanation, has beendescribed with reference to specific embodiments. However, theillustrative discussions above are not intended to be exhaustive or tolimit embodiments of the disclosed subject matter to the precise formsdisclosed. Many modifications and variations are possible in view of theabove teachings. The embodiments were chosen and described in order toexplain the principles of embodiments of the disclosed subject matterand their practical applications, to thereby enable others skilled inthe art to utilize those embodiments as well as various embodiments withvarious modifications as may be suited to the particular usecontemplated.

What is claimed is:
 1. A system, comprising: A rear camera of a mobiledevice configured to capture at least one frame that includes a face ofa user; a database configured to store the at least one frame; aprocessor communicatively coupled to the rear camera and the database,the processor configured to: detect the face in the captured at leastone frame; extract a left eye image and a right eye image of the facefrom the at least one frame; resize the left eye image to a sizematching one of a calibrated set of left eye images for the user and theright eye image to a size matching one of a calibrated set of right eyeimages for the user; compare the resized left eye image to thecalibrated set of left eye images for the user, wherein each image inthe calibrated set of left eye images corresponds to a known eye gazedirection for a left eye of the user; compare the resized right eyeimage to the calibrated set of right eye images for the user, whereineach image in the calibrated set of right eye images corresponds to aknown eye gaze direction for a right eye of the user; determine adirection of eye gaze based upon the comparison of the resized left eyeimage to the calibrated set of images for the left eye and thecomparison of the resized right eye image to the calibrated set ofimages for the right eye; identify, based upon the determination of thedirection of eye gaze and a known configuration of an eye gaze boardhaving a plurality of quadrants, a quadrant of the eye gaze boardcorresponding to the direction of eye gaze, wherein each of theplurality of quadrants of the eye gaze board comprise at least onecharacter; and display the at least one character from the quadrant as apart of a text-based message.
 2. The system of claim 1, the processor isfurther configured to generate the calibration template comprising thecalibrated set of left eye images and the calibrated set of right eyeimages, comprising: receive an indication of eye gaze of the user in adirection; receiving a second at least one frame of the user that iscaptured from the rear camera; detect the face of the user in the secondat least one frame; extract a calibrated left eye image and a calibratedright eye image of the face from the second at least one frame; andstore the calibrated left eye image and the calibrated right eye imageto the database as part of the calibration template for the direction ofeye gaze.
 3. The system of claim 2, the processor further configured to:determine lighting condition based on an amount of light detected by therear camera; and associate the lighting condition with the calibrationtemplate.
 4. The system of claim 1, the processor further configured to:based upon the at least one character in the quadrant, determine atleast one word associated with the at least one character using apredictive text algorithm that determines words based upon frequency ofusage.
 5. The system of claim 4, the processor further configured to:align landmarks to the face in the captured at least one frame.
 6. Thesystem of claim 1, the processor further configured to: cause an audibleor visible indication of the at least one character.
 7. The system ofclaim 1, the processor further configured to: receive a gesture from theuser; and perform an action based upon the gesture.
 8. The system ofclaim 7, wherein the action is to delete the at least one character fromthe text-based message.
 9. The system of claim 1, the processor furtherconfigured to: convert the left eye image to hue, saturation, and value(HSV) color space and retain only the value portion; and convert theright eye image to HSV color space and retain only the value portion.10. The system of claim 1, the processor further configured to:receiving a plurality of eye gazes from the user to form a sequence ofeye gazes; and predicting a word based upon the sequence of eye gazesusing a predictive text algorithm.
 11. A computer-implemented method,comprising: capturing, by a rear camera of a mobile device, at least oneframe that includes a face of a user; detecting the face in the capturedat least one frame; extracting a left eye image and a right eye image ofthe face from the at least one frame; resizing the left eye image to asize matching one of a calibrated set of left eye images for the userand the right eye image to a size matching one of a calibrated set ofright eye images for the user; comparing the resized left eye image tothe calibrated set of left eye images for the user, wherein each imagein the calibrated set of left eye images corresponds to a known eye gazedirection for a left eye of the user; comparing the resized right eyeimage to the calibrated set of right eye images for the user, whereineach image in the calibrated set of right eye images corresponds to aknown eye gaze direction for a right eye of the user; determining adirection of eye gaze based upon the comparison of the resized left eyeimage to the calibrated set of images for the left eye and thecomparison of the resized right eye image to the calibrated set ofimages for the right eye; identifying, based upon the determination ofthe direction of eye gaze and a known configuration of an eye gaze boardhaving a plurality of quadrants, a quadrant of eye gaze boardcorresponding to the direction of eye gaze, wherein each of theplurality of quadrants of the eye gaze board comprise at least onecharacter; and displaying the at least one character from the quadrantas a part of a text-based message.
 12. The method of claim 11, furthercomprising generating the calibration template comprising the calibratedset of left eye images and the calibrated set of right eye images,comprising: receiving an indication of eye gaze of the user in adirection; capturing a second at least one frame of the user, detectingthe face of the user in the second at least one frame; extracting acalibrated left eye image and a calibrated right eye image of the facefrom the second at least one frame; and storing the calibrated left eyeimage and the calibration right eye image as part of the calibrationtemplate for the direction of eye gaze.
 13. The method of claim 12,further comprising: determining lighting condition based on an amount oflight detected by the rear camera; and associating the lightingcondition with the calibration template.
 14. The method of claim 13,further comprising: based upon the at least one character in thequadrant, determining at least one word associated with the at least onecharacter using predictive text algorithm that determines words basedupon frequency of usage.
 15. The method of claim 14, further comprising:receiving a selection of at least one word associated with the at leastone character.
 16. The method of claim 11, further comprising:generating an audible or visible indication of the at least onecharacter.
 17. The method of claim 11, further comprising: receiving agesture from the user; and performing an action based upon the gesture.18. The method of claim 11, further comprising: converting the left eyeimage to hue, saturation, and value (HSV) color space and retain onlythe value portion; and converting the right eye image to HSV color spaceand retain only the value portion.
 19. The method of claim 11, furthercomprising: receiving a plurality of eye gazes from the user to form asequence of eye gazes; and predicting a word based upon the sequence ofeye gazes using a predictive text algorithm.
 20. A non-transitorycomputer readable medium having stored thereon computer readableinstructions that are executable to cause one or more processors toperform operations, comprising: capturing, by a rear camera of a mobiledevice, at least one frame that includes a face of a user; detecting theface in the captured at least one frame; extract a left eye image and aright eye image of the face from the at least one frame; resizing theleft eye image to a size matching one of a calibrated set of left eyeimages for the user and the right eye image to a size matching one of acalibrated set of right eye images for the user; comparing the resizedleft eye image to the calibrated set of left eye images for the user,wherein each image in the calibrated set of left eye images correspondsto a known eye gaze direction for a left eye of the user; comparing theresized right eye image to the calibrated set of right eye images forthe user, wherein each image in the calibrated set of right eye imagescorresponds to a known eye gaze direction for a right eye of the user;determining a direction of eye gaze based upon the comparison of theresized left eye image to the calibrated set of images for the left eyeand the comparison of the resized right eye image to the calibrated setof images for the right eye; identifying, based upon the determinationof the direction of eye gaze and a known configuration of an eye gazeboard having a plurality of quadrants, a quadrant of the eye gaze boardcorresponding to the direction of eye gaze, wherein each of theplurality of quadrants of the eye gaze board comprise at least onecharacter; and displaying the at least one character from the quadrantas a part of a text-based message.